<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>js控制台练习</title>
</head>
<body>
    <button onclick="test1()">按钮</button>
    <script>

        function test1(){
            test2(1,2);
            let a = 1;
            let b = 2;
        }
        function test2(a,b){
            let num = a+b;
            test3(1,2);
        }
        function test3(a,b){
            let num = a+b;
            
            console.log('111',1,2);
            
        }
    </script>
</body>
</html>